Application:SBromwichKernel

The sbromwich series of kernels are the kernels I run on my phone with all current webos-internals testing patches applied, plus my patches, plus my kernel configuration.

The kernels are currently available at http://ipkg.preware.org/feeds/webos-kernels/testing/1.4.1.1/ and can be added using any standard package manager in the standard format (deducing this is left as an exercise for the reader).

Patches applied for 1.4.1-26 ("yoda")

• wfi instruction re-enabled after several sources confirmed it did not hinder
• Tweaked timeouts for prcm bitbanging, particularly with DOM_PER to see if that reduces battery drain at the expense of (possibly) more hangs coming out of suspend.

Patches applied for 1.4.1-25 ("adric")

• wfi instruction on prcm fail removed to validate if this is a regression causing battery drain.

Patches applied for 1.4.1-24 ("jangofett")

• Reduce number of scheduling calls made to try to reduce battery drain. This may have an adverse affect on wake from suspend.

Patches applied for 1.4.1-23 ("bobafett")

• Debug settings removed from default kernel build.
• Compile kernel with explicit cortex-a8 tuning flags for gcc.
• Tweak prcm power manager to more explicitly wait for power set calls to return, remove debug cruft, and add Wait For Interrupt instruction if a prcm setting attempt fails.
• Enable preempt kernel.

Known problems

• Pre can take some extra time to respond to certain activities, especially when waking up; lags of up to 2 seconds can be experienced on wakeup. The alternative is a reboot, which will take even longer.

Improvements

• User interactivity latency should be lower (time to respond to keypresses, etc).
• Fewer powerd wakeups allowing the system to sleep longer.

Warnings

• My patch makes the kernel boot at 800MHz. Run this kernel at your own risk. Not compliant with point 6 of http://forums.precentral.net/webos-internals/241355-next-generation-kernel-development-packaging.html .
• anticipatory io scheduler recommended.
• Install SmartReflex patches at your own risk. SmartReflex is not expected to work.
• Some users have reported increased battery usage when running this kernel.

Settings used with this kernel

I use the following event.d script:

description "Local tuning modes"
start on stopped finish
stop on runlevel [!2]
console none
script
# Set governor
echo "performance" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
# Set min frequency
echo 250000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
# Set max frequency
echo 800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
# Set io scheduler to anticipatory
echo anticipatory > /sys/block/mmcblk0/queue/scheduler
# Powertop Suggestion: increase the VM dirty writeback time from 5.00 to 15
# seconds. 0.50s works better on flash as it has slow writes. Needs more testing.
echo 50 > /proc/sys/vm/dirty_writeback_centisecs
# Use YeaH TCP as it's fairer over wireless
echo yeah >  /proc/sys/net/ipv4/tcp_congestion_control
# Don't cache route metrics since we're mobile
echo 1 > /proc/sys/net/ipv4/tcp_no_metrics_save
# Ramp up the tx/rx network buffers in case we get bursty
echo 1048576 > /proc/sys/net/core/rmem_max
echo 1048576 > /proc/sys/net/core/wmem_max
echo 3000 > /proc/sys/net/core/netdev_max_backlog
nohup /usr/local/bin/pt.pl > /dev/null 2>&1 &
/usr/sbin/iptables -D INPUT -i eth0 -p tcp --sport 5222 -s 205.140.203.0/24 -j ACCEPT  > /dev/null 2>&1
/usr/sbin/iptables -I INPUT -i eth0 -p tcp --sport 5222 -s 205.140.203.0/24 -j ACCEPT
echo 5 > /proc/sys/vm/laptop_mode
end script
# end of file

In addition, I am using my naive perl scheduler at http://www.fop.ns.ca/pre/pt/pt.pl to manage the CPU frequency.